173 Ino

173 Ino is a large main-belt asteroid that was discovered by French astronomer Alphonse Borrelly on August 1, 1877, and named after Ino, a queen in Greek mythology. The adjectival form of the asteroid name is Inoan. Categorized as a C-type asteroid from its spectrum, 173 Ino has a dark surface and a primitive carbonaceous composition.

Multiple photometric studies of this asteroid were performed between 1978 and 2002. The combined data gave an irregular, asymmetrical light curve with a period of 6.163 ± 0.005 hours and a brightness variation of 0.10–0.15 in magnitude. The asteroid is rotating in a retrograde direction.